Rocking control device for two front wheels rocking vehicle

ABSTRACT

A rocking control device for a two front wheels rocking vehicle includes a high rigidity self-standing controller that executes a high rigidity self-standing control that locks the rocking of the two front wheels rocking vehicle and that assists a self-standing of the two front wheels rocking vehicle, a switch that switches the high rigidity self-standing control to ON or OFF state, and an offset cancellation controller that executes an offset cancellation control that maintains the self-standing state of the two front wheels rocking vehicle until a predetermined traveling state when the high rigidity self-standing control is switched off.

CROSS-REFERENCE TO RELATED APPLICATION

Priority is claimed on Japanese Patent Application No. 2016-191066,filed Sep. 29, 2016, the content of which is incorporated herein byreference.

BACKGROUND Field of the Invention

The present invention relates to a rocking control device for a twofront wheels rocking vehicle.

Description of Related Art

In the related art, in a rocking control device for a two front wheelsrocking vehicle, a technology of performing rocking assistance accordingto a vehicle speed is known (for example, Japanese Unexamined PatentApplication, First Publication No. 2010-143474).

SUMMARY

Incidentally, in the related art, when control of turning offself-standing control during rocking lock is performed, rocking of avehicle may occur when self-standing assistance stops abruptly.

An aspect of the present invention is provided to suppress variation inroll posture when self-standing assistance stops in a rocking controldevice for a two front wheels rocking vehicle.

A rocking control device for a two front wheels rocking vehicleaccording to the present invention employs the following configurations.

(1) A rocking control device for a two front wheels rocking vehicleaccording to an aspect of the present invention is a rocking controldevice for a two front wheels rocking vehicle comprising a pair of leftand right front wheels and configured to laterally rock a vehicle body,the rocking control device for a two front wheels rocking vehicleincluding a high rigidity self-standing controller that executes a highrigidity self-standing control that locks the rocking of the two frontwheels rocking vehicle and that assists a self-standing of thetwo-wheeled rocking vehicle, a switch that switches the high rigidityself-standing control to ON or OFF state and an offset cancellationcontroller that executes an offset cancellation control that maintainsthe self-standing state of the two front wheels rocking vehicle until apredetermined traveling state is established when the high rigidityself-standing control is switched off.

According to this above mentioned configuration of (1), when the highrigidity self-standing control is turned off during the high rigidityself-standing control, since self-standing assistance of the highrigidity self-standing control is maintained until a vehicle speed, adistance traveled, and so on, becomes to a predetermined travelingstate, variation in roll posture when the high rigidity self-standingcontrol is released can be suppressed.

(2) In the aspect of above mentioned (1), the high rigidityself-standing control may be released when a vehicle speed of the twofront wheels rocking vehicle exceeds a predetermined speed.

According to this above mentioned configuration of (2), as the rockinglock is released when the predetermined speed is exceeded, anappropriate rollable driving state can be provided even when the rockinglock is applied on a downhill road or the like.

(3) In the aspect of above mentioned (1) or (2), a self-standingauxiliary spring controller that executes a self-standing auxiliaryspring control that applies a restricting force to a rocking of the twofront wheels rocking vehicle and that suppresses the rocking of the twofront wheels rocking vehicle before reaching the high rigidityself-standing control may be provided.

According to this above mentioned configuration of (3), since the twofront wheels rocking vehicle reaches the high rigidity self-standingcontrol via the self-standing auxiliary spring control working in adirection in which the rocking of the two front wheels rocking vehicleis suppressed, self-standing properties can be enhanced while allowingrolling of the vehicle body, and the two front wheels rocking vehiclecan be naturally guided toward self-standing.

(4) In the aspect of above mentioned (3), the self-standing auxiliaryspring control may strengthen a rocking restricting force according to adecrease of a vehicle speed.

According to this above mentioned configuration of (4), the two frontwheels rocking vehicle can be gradually guided to self-standingaccording to a decrease of the vehicle speed while allowing rolling ofthe vehicle body.

(5) In the aspect of any one of above mentioned (1) to (4), the offsetcancellation control may weaken a rocking restricting force according toan increase of the vehicle speed.

According to this above mentioned configuration of (5), since rolling isallowed gradually according to an increase of the vehicle speed, it ispossible to transition to a naturally rollable state while variationduring release of the rocking lock is suppressed.

According to the aspects of the present invention, in the rockingcontrol device for a two front wheels rocking vehicle, variation in rollposture when the self-standing assistance is terminated can besuppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side view of a two front wheels rocking vehicleaccording to an embodiment of the present invention.

FIG. 2 is a left side view of a two front wheels suspension system ofthe two front wheels rocking vehicle.

FIG. 3 is a view seen from an arrow III of FIG. 2 (a front view from anaxial direction of upper and lower rocking shafts).

FIG. 4 shows graphs showing roll control of the two front wheels rockingvehicle, part (a) shows first rocking control, and parts (b) to (d) showsecond rocking control.

FIG. 5 is a view for describing a second rocking control switch of thetwo front wheels rocking vehicle.

FIG. 6 is a schematic diagram for describing a control block of the twofront wheels rocking vehicle.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be describedbased on the accompanying drawings. Further, directions of forward,rearward, left, right, and so on, described below are the same asdirections in a vehicle described below unless the context clearlyindicates otherwise. In addition, in appropriate places in the drawingsused in the following description, an arrow FR showing a forwarddirection with respect to a vehicle, an arrow LH showing a leftwarddirection with respect to the vehicle and an arrow UP showing an upwarddirection with respect to the vehicle are provided.

As shown in FIG. 1 to FIG. 3, a two front wheels rocking vehicle 1according to an embodiment is configured as a two front wheels saddleriding type vehicle in which a pair of left and right front wheels(steering wheels) 2L and 2R are laterally symmetrically provided in afront section of a vehicle body, a single rear wheel (a drive wheel) 3is provided at a center of a rear section of the vehicle body in aleftward/rightward direction, and the vehicle body can be rockedlaterally (rolling motion). The two front wheels rocking vehicle 1 has alaterally symmetrical configuration unless the context clearly indicatesotherwise. In the embodiment, a pair of left and right components isdistinguished by adding the reference character L to the left componentand the reference character R to the right component, and only referencenumerals from which “L” and “R” are removed may be indicated.

A vehicle body frame 5 of the two front wheels rocking vehicle 1includes a front suspension frame body 20 configured to support a twofront wheels suspension system 4 in a front end portion of the vehiclebody frame 5, left and right main frames 13 extending rearward anddownward from an upper section of the front suspension frame body 20while branching off leftward and rightward, left and right down frames14 extending rearward and downward from a lower section of the frontsuspension frame body 20 while branching off leftward and rightward,left and right pivot frames 15 extending downward from rear end portionsof the left and right main frames 13, and a seat frame 16 extendingrearward and upward from upper sections of the left and right pivotframes 15.

An engine (an internal combustion engine) 6 serving as a prime mover ofthe two front wheels rocking vehicle 1 is mounted below the main frames13. A rear wheel 3 driven by power from the engine 6 is supported byrear end portions of swing arms 7. Front end portions of the swing arms7 are vertically swingably supported by the left and right pivot frames15. A knee grip section 8 sandwiched between both knees of a rider (adriver) is disposed over the engine 6, and an occupant seat 9 isdisposed behind the knee grip section 8. The knee grip section 8 isconstituted by a fuel tank of the engine 6, an article storage box, orthe like.

A head pipe 12 through which a steering shaft 12 a is supported isinstalled on a rear section of the front suspension frame body 20. A bartype steering handle 11 is attached to an upper end portion of thesteering shaft 12 a protruding upward from the head pipe 12. A bottombracket 12 b to which a steering link mechanism 18 is connected isattached to a lower end portion of the steering shaft 12 a protrudingdownward from the head pipe 12. Left and right front fork units 28 areconnected to the steering link mechanism 18 via left and right tie rods19L and 19R. Line C1 of the drawing represents a central axis (asteering axis) of the head pipe 12 and the steering shaft 12 a.

An upper rocking shaft 25 passing through a lateral center of anintegrated upper arm 24 in the two front wheels suspension system 4 issupported to the upper section of the front suspension frame body 20. Alower rocking shaft 27 coaxially passing through left and right innerend portions of left and right lower arms 26L and 26R, which areseparated at left and right sides, in the two front wheels suspensionsystem 4 is supported to the lower section of the front suspension framebody 20. The upper and lower rocking shafts 25 and 27 are parallel toeach other and inclined forward and upward.

The upper arm 24 and left and right lower arms 26 of the two frontwheels suspension system 4 extend leftward and rightward in front of thehead pipe 12. Upper sections of left and right front fork units 28L and28R that independently suspend the left and right front wheels 2L and 2Rare supported to the upper arm 24 and left and right outer end portionsof the left and right lower arms 26 such that they may be steered. Theleft and right front fork units 28L and 28R can be steered via left andright steering shafts (king pin shafts) 29L and 29R parallel to the headpipe 12 and offset forward and outward from the head pipe 12 when seenin a side view of the vehicle. Reference characters C4L and C4R in thedrawing represent central axes (king pin axes) of the left and rightsteering shafts 29L and 29R.

The two front wheels suspension system 4 can laterally rock a vehiclebody main body 1A including the vehicle body frame 5, the engine 6, therear wheel 3, and so on, while the left and right front wheels 2L and 2Rremain in contact with the ground, and can laterally rock the left andright front fork units 28L and 28R and the left and right front wheels2L and 2R to match the lateral rocking of the vehicle body main body 1A.Here, the two front wheels suspension system 4 alternately verticallymoves the left and right front fork units 28L and 28R and the left andright front wheels 2L and 2R with respect to the vehicle body main body1A. Line CL of the drawing represents a lateral central surface of thevehicle body.

The left and right front fork units 28L and 28R constitute a leadinglink type front suspension which laterally approaches the inner sides ofthe left and right front wheels 2L and 2R. The left and right front forkunits 28L and 28R include fork main bodies 31 having upper sectionssupported by the upper arm 24 and left and right outer end portions ofthe left and right lower arms 26, leading arms 32 having rear endportions that are swingably supported by lower end portions of the forkmain bodies 31, cushion units 33 configured to bridge the leading arms32 and the fork main bodies 31, front wheel axles 34 integrallyswingably installed on front end portions of the leading arms 32,caliper brackets 35 swingably supported by the front wheel axles 34while supporting brake calipers 36 in front of the front wheel axles 34,and torque rods 37 configured to bridge the caliper brackets 35 and thefork main bodies 31 above the front wheel axle 34.

King pin axes C4 of left and right steering shafts 29 are inclined to bedisposed further backward as they go upward in a vertical direction whenseen in a side view of the vehicle. In other words, left and right kingpin axes C4L and C4R are inclined to be parallel to a steering axis C1.The left and right king pin axes C4L and C4R extend in the verticaldirection when seen in a front view of the vehicle.

An extension portion extending downward from the king pin axis C4 whenseen in a side view of the vehicle reach an intersection point T1′ infront of a ground contact point T1 of the front wheel 2 with respect toa road surface R and a predetermined trail amount is generated. Aninclined angle θ of the king pin axis C4 with respect to the verticaldirection when seen in a side view of the vehicle is a caster angle. Thefront wheel axle 34 is offset forward from the extension point of theking pin axis C4 when seen in a side view of the vehicle.

The two front wheels rocking vehicle 1 includes an actuator 41configured to control lateral rocking (rolling) of the vehicle body.

The actuator 41 has a rotary drive shaft 42 parallel to the upper andlower rocking shafts 25 and 27 of the two front wheels suspension system4. The actuator 41 fixes a housing that functions as a frame configuredto receive and support the rotary drive shaft 42 to a portion of thefront suspension frame body 20 above the upper rocking shaft 25. Theactuator 41 is an electric motor or a fluidic device configured togenerate a torque in the rotary drive shaft 42, and integrally supportsa rocking arm 43 on the rotary drive shaft 42. A portion of the upperarm 24 offset from the upper rocking shaft 25 toward one of left andright sides is connected to the rocking arm 43 via a connecting link 44.The upper and lower rocking shafts of the connecting link 44 and an areathat connects the rotary drive shaft 42 and the upper rocking shaft 25form a parallel link when seen in a side view of the vehicle, the upperarm 24 is rocked according to a rotation angle of the rotary drive shaft42, and thus, rolling of the vehicle body is controlled.

Next, roll control (lateral rocking control) of the two front wheelsrocking vehicle 1 will be described.

As shown in FIG. 4, roll control of the two front wheels rocking vehicle1 is generally classified as first rocking control (self-standing OFFcontrol, part (a) of FIG. 4) of assisting a roll operation of a rider,and second rocking control (self-standing ON control, parts (b) to (d)of FIG. 4) allowing self-standing a vehicle body without support by adriver during stoppage.

Referring to part (a) of FIG. 4, the first rocking control includesweight shift roll assist control L1 and dual effect roll damper controlL2 performed during stoppage and reducing an effect strength shortlyafter the start of traveling, and steering roll assist control L4 andsingle effect roll damper control L3 that are not performed duringstoppage and increasing an effect strength instead of a decrease of theeffect strength of the weight shift roll assist control L1 and the dualeffect roll damper control L2.

The first rocking control can be turned on/off by a first rockingcontrol switch (not shown) attached to a handle, a vehicle body, or thelike, and it is needless to say that the form of the switch is notlimited.

The first rocking control and the second rocking control can be causedto operate in combination, and when the first rocking control and thesecond rocking control are turned on together, in a predetermined speedrange in which self-standing auxiliary spring control L5 works, each ofthe weight shift roll assist control L1, the dual effect roll dampercontrol L2, the single effect roll damper control L3 and the steeringroll assist control L4 also works in the same way.

Referring to FIG. 4(b), FIG. 4(d) and FIG. 5, the second rocking controlis performed when a second rocking control switch (a self-standingON/OFF switch) 45 is turned on and when it has become to a predeterminedtraveling state such as a vehicle speed is below a predetermined value.For example, when a throttle grip 11 a is used as an operating piece,the second rocking control switch 45 of the embodiment is turned off(OFF) from a fully closed position of the throttle grip 11 a (a throttlefully closed position) toward an operation range in a throttle openingdirection, and is turned on (ON) when over-stroked further from thefully closed position in the throttle closing direction. That is, athrottle is fully closed when the second rocking control switch 45 isturned on.

The second rocking control includes the self-standing auxiliary springcontrol L5 in which the effect strength is gradually increased as avehicle speed is decreased from a time point when the vehicle speed hasreached a low speed (for example, 15 km/h) during deceleration when thesecond rocking control switch 45 is turned on, and high rigidityself-standing control L6 in which the effect strength is increased to apredetermined value from a time point when the vehicle speed has reachedan ultra low speed (for example, 3 km/h) until the stoppage of thevehicle during deceleration when the second rocking control switch 45 isturned on.

The self-standing auxiliary spring control L5 overlaps with the steeringroll assist control L4. In a speed range exceeding a predetermined speedof the self-standing auxiliary spring control L5, the steering rollassist control L4 is continued even when the second rocking controlswitch 45 is turned on. Here, the weight shift roll assist control L1,the dual effect roll damper control L2 and the single effect roll dampercontrol L3 are also continued.

In the high rigidity self-standing control L6, various roll momentsapplied to the vehicle body are suppressed by a control system. That is,in the high rigidity self-standing control L6, it is possible to lockthe rocking of the two front wheels rocking vehicle 1 and to assist therocking of the two front wheels rocking vehicle 1 to self-stand. Forthis reason, when the high rigidity self-standing is released, thevarious roll moments cannot be suppressed simultaneously. Here, in thesecond rocking control, offset cancellation control L7 (see part (c) ofFIG. 4) that stores a rocking torque instruction value during the highrigidity self-standing and that applies the same rocking torque at thetime of releasing the self-standing in order to gradually decrease therocking torque is performed.

Referring to part (c) of FIG. 4, the offset cancellation control L7gradually reduces a rocking restricting force according to an increasein vehicle speed, and terminates at a time point, for example, when thevehicle has traveled a predetermined distance (for example, 9 m) afterstarting the control. The offset cancellation control L7 outputs a valueof “0” until a predetermined storage condition is input.

Here, the high rigidity self-standing control L6 maintains the highrigidity self-standing until the vehicle speed has reached apredetermined speed (for example, 3 km/h) even when the vehicle travelswhile the second rocking control switch 45 is not turned off (line L6′in the drawing) and releases the high rigidity self-standing when thevehicle speed exceeds the predetermined speed. The high rigidityself-standing control L6 is released when a vehicle speed of the twofront wheels rocking vehicle exceeds a predetermined speed. Also at thistime, the offset cancellation control L7 outputs a stored value by usingthe release of the high rigidity self-standing as a trigger (line L7′ inthe drawing). In addition, when the previously stored value is lowered,a new value is not input until the next storage condition is satisfied.The offset cancellation control L7 maintains the self-standing state ofthe two front wheels rocking vehicle 1 until a predetermined travelingstate is established when the high rigidity self-standing control L6 isswitched off.

Next, a control block of the two front wheels rocking vehicle 1 will bedescribed.

As shown in FIG. 6, various information such as a vehicle speed, on/offof the second rocking control switch 45, a roll rate (an angularvelocity), a roll angle, a steering force and a steering angle is inputto a rocking control ECU 50. A weight shift roll assist controller 51, adual effect roll damper controller 52, a steering roll assist controller54, a single effect roll damper controller 53, a self-standing auxiliaryspring controller 55, a high rigidity self-standing controller 56 and anoffset cancellation controller 57 are installed in the rocking controlECU 50.

In the weight shift roll assist controller 51, a state in which a weightshift of a rider can be balanced during stoppage, i.e., a state in whichinclination of the vehicle body follows the weight shift of the rider iscreated, and a transition from stoppage to traveling can be performedwithout stepping the ground with a foot (the weight shift roll assistcontrol L1).

In the weight shift roll assist control L1, a weight shift amount(calculated by a rocking torque, a roll rate, a roll angle, a steeringangle and a vehicle speed) and a vehicle speed are input information.The rocking torque is detected by, for example, a torque sensorinstalled in the vicinity of the upper and lower rocking shafts 25 and27 in the two front wheels suspension system 4, the roll rate and theroll angle are detected by, for example, a gyro sensor installed on thevehicle body, the steering angle and the steering force are detected by,for example, a steering angle/steering force sensor installed in thevicinity of the steering shaft 12 a, and the vehicle speed is detectedby, for example, a vehicle speed sensor installed in the vicinity of thefront wheel axle 34.

In the weight shift roll assist control L1, a rocking torque inproportion to an estimated roll moment value due to a weight shift of arider is instructed. In actuality, the weight shift itself is notinstructed, and a total value (an estimated weight shift amount and anestimated external force moment) of the moment applied to the vehiclebody other than from the rocking unit is estimated, and an instructionvalue (a weight shift roll assist instruction value) of the rockingtorque is output based on the estimated total value. The output valuerefers to a map in which the effect strength is set according to avehicle speed. In the embodiment, each of the controllers has a similarmap.

Further, in consideration of a roll angle with respect to a rockingreference position, when an instruction value of the rocking torque is avalue indicating an output of the rocking torque toward a side at whichthe vehicle body is tilted toward the ground, a rocking torqueinstruction value is fixed to zero. That is, the rocking torque is onlyoutput toward a side that the vehicle body is raised, and rolling to theside where the vehicle body is tilted toward the ground is not assisted.Specifically, when the vehicle body rolls rightward from the rockingreference position and the weight shift is directed rightward or whenthe vehicle body rolls leftward from the rocking reference position andthe weight shift is directed leftward, the rocking torque instructionvalue is set to zero. Since the torque toward the side where the vehiclebody is tilted toward the ground is fixed to zero, even when input of atorque toward the side where the vehicle body is tilted toward theground is caused due to a reaction with respect to the weight shift inorder to raise the vehicle body, the influence with respect to anoperation of raising the vehicle body is suppressed.

An assistance force of the first rocking control is not applied in adirection in which the vehicle body is tilted toward the ground from therocking reference position and is applied only in a direction in whichthe vehicle body is raised toward the reference position. The rockingreference position is a rocking position at which a vertical axis (anaxis in the vertical direction) coincides with a vehicle body lateralcentral surface CL during stoppage, and is a rocking position at whichan inclined axis inclined with respect to the vertical axis by apredetermined angle in the steering direction coincides with the vehiclebody lateral central surface CL when the vehicle travels with a steeringangle (during turns). The rocking reference position during turning isdetermined based on a rocking reference position map in which a steeringangle and a vehicle speed are used as parameters. The rocking referenceposition is a rocking balanced position at which rocking moments of thevehicle body are canceled out in the lateral direction.

For example, when a leftward steering angle is applied, the front wheels2L and 2R are inclined leftward from setting of the caster angle and thetrail amount, and the vehicle body and the rider will start movingleftward with respect to the ground contact points T1L and T1R of thefront wheels 2L and 2R. With respect to this, the rider will naturallymove rightward in order to balance in a self-standing state. Providedthat a self-standing rocking angle obtained as a result of this movementof the rider is a balance reference angle, in the embodiment, a rockingangle less than the balance reference angle is set as a dead zone forthe weight shift roll assist control L1.

In the weight shift roll assist control L1, there is a case where thereaction may be delayed. In addition, since the rocking torqueinstruction rises after the weight shift of the rider has terminated,there is a case where the reaction may be delayed after the operation.In addition, since the torque is merely applied to the vehicle bodyrolling, it is necessary to provide an element configured to stop therolling after the rolling starts to proceed. For these reasons, it ispreferable to use the weight shift roll assist control L1 together withthe dual effect roll damper control L2.

In the dual effect roll damper controller 52, traveling stability isincreased by improving the stability of rolling (the dual effect rolldamper control L2). In the dual effect roll damper control L2, the rollrate and the vehicle speed are input information. In the dual effectroll damper control L2, as a rocking torque (a damping torque) ofreverse polarity is instructed in proportion to the roll rate, abehavior of viscous friction is reproduced.

In the single effect roll damper controller 53, wobbling is reduced bymaking tilting of the vehicle body gentle during, in particular, lowspeed turning (the single effect roll damper control L3). In the singleeffect roll damper control L3, the roll rate, the roll angle, thevehicle speed and the steering angle are input information. In thesingle effect roll damper control L3, like the dual effect roll dampercontrol L2, as a rocking torque (a damping torque) of reverse polarityis instructed in proportion to the roll rate, a behavior of the viscousfriction is reproduced. In the single effect roll damper control L3, atorque resisting against the side at which the vehicle body is tiltedtoward the ground is generated, but a control which interferes with theside at which the vehicle body is raised is not performed.

For example, when the vehicle is traveling in a rightward inclinationstate, the vehicle body angular velocity is rightward, and when thevehicle is traveling in a leftward inclination state, the vehicle bodyangular velocity is leftward. Accordingly, a switching circuit sw3determines whether the vehicle body angular velocity is rightward orleftward.

In the steering roll assist controller 54, a roll reaction with respectto the steering (a reaction of rolling in a direction opposite to thesteering direction) is created by a motor torque (the steering rollassist control L4). For this reason, roll controllability can bemaintained up to a low speed range in which normally a counter steeringbecomes not effective, and it is possible to keep the vehicle bodyrocking under a rider's control. However, since a rider's discomfort isincreased when the steering roll assist control L4 is performed at avehicle speed of zero, the weight shift roll assistance is performedwhen the vehicle speed is about zero instead of the steering rollassistance.

In the steering roll assist control L4, the steering force and thesteering angle are input information.

In the steering roll assist control L4, a rocking torque in a directionopposite to the steering force direction (a left roll torque when asteering force is in a rightward direction, and a right roll torque whena steering force is in a leftward direction) is instructed in proportionto the steering force. The instruction value is increased or decreasedaccording to the steering angle, a proportional coefficient is decreasedin the vicinity of traveling in a straight line, and a proportionalcoefficient is increased as the steering angle is increased.

The second rocking control switch 45 transmits a balancing intention ofa rider to a control system. That is, when self-standing is releasedwith only conditions such as a vehicle speed or the like, the rider'sbalancing may not be in time. With respect to this, by making the riderto indicate the rider's intention through the second rocking controlswitch 45, it is possible to make the rider to prepare for balancing andsuppress the delay for starting the balancing.

In addition, since the second rocking control switch 45 has the throttlegrip 11 a serving as an operating part, it is not necessary for a riderto change the position of the hand for handling, and the vehicle can bestarted immediately after release of self-standing. In addition, therider's self-standing intention can be transmitted to the control systemin a series of the accelerator OFF operation during stoppage. Inaddition, operations during driving are also easy, and ON/OFF of thesecond rocking control can be directly controlled according to therider's intention.

In the self-standing auxiliary spring controller 55, the vehicle body isguided to a vertical standing state (a standing state in the verticaldirection) in preparation for self-standing during stoppage whileallowing rolling at a low speed before the stoppage (the self-standingauxiliary spring control L5). The self-standing auxiliary springcontroller (55) executes a self-standing auxiliary spring control (L5)that applies a restricting force to a rocking of the two front wheelsrocking vehicle (1) and that suppresses the rocking of the two frontwheels rocking vehicle (1) before reaching the high rigidityself-standing control (L6). In the self-standing auxiliary springcontrol L5, the roll angle and the vehicle speed are input information.In the self-standing auxiliary spring control L5, a rocking torque witha reverse polarity in proportion to the roll angle is instructed. Inaddition, the self-standing auxiliary spring control L5 works when thesecond rocking control switch 45 is turned on. The self-standingauxiliary spring control L5 strengthens a rocking restricting forceaccording to a decrease of a vehicle speed.

In the high rigidity self-standing controller 56, a necessity for arider to support the vehicle body during stoppage is eliminated (thehigh rigidity self-standing control L6). In the high rigidityself-standing control L6, the roll angle, the roll rate and the vehiclespeed are input information. In the high rigidity self-standing controlL6, regardless of a center of gravity of the vehicle body and the rider,a rocking torque is instructed such that a geometric center of thevehicle body is disposed on a vertical axis. The high rigidityself-standing control L6 is positioning control having a positioning(roll angle) loop and a speed (roll rate) loop, and has the same effectas a combination of a rigid roll damper and a rigid roll spring.

In the offset cancellation controller 57, the rocking torque instructionvalue, the roll rate and the vehicle speed are input information. In theoffset cancellation control L7, in a state in which the second rockingcontrol switch 45 is turned on, the roll rate is about zero and avehicle speed of zero continues for 0.5 sec or more, the switchingcircuit is closed, and memory update with respect to a capture of arocking torque instruction value is started. When the second rockingcontrol switch 45 is turned off, the memory update is canceled and thestored instruction value is added to the instructed torque. The storedinstruction value is decreased along with, for example, the traveling ofthe vehicle, and is made zero after a predetermined distance has beentraveled (about 9 m). In addition, when the second rocking controlswitch 45 is turned off, an offset value (bias) is set to 0 and added tothe instructed torque.

The stored rocking torque instruction value includes all influencesrelated to the roll moment such as a cant gradient at that time, anoffset of the rocking torque, a stepping state of the rider using afoot, a center of gravity of a rider, a steering angle (a ground contactposition), and so on.

Next, operations will be described.

When only the first rocking control switch is turned on, while theweight shift roll assist control L1 and the dual effect roll dampercontrol L2 reduce the effect strength shortly after the start oftraveling, the weight shift roll assist control L1 maintains the effectcontinuing during low speed traveling. Accordingly, even when thevehicle body is inclined and the rider uses a foot during low speedtraveling, raising the vehicle body by the rider with the usage of thefoot can be assisted by the weight shift roll assist control L1. Theweight shift roll assist control L1 is continued to about 10 km/h, thesingle effect roll damper control L3 is continued to about 15 km/h, andthe dual effect roll damper control L2 is continued to about 20 km/h.

In addition, after the vehicle has started traveling, the steering rollassist control L4 raises the effect strength thereof so as to replacethe weight shift roll assist control L1 or the like. Accordingly, it ispossible to make the vehicle body rocking under the rider's controlwhile maintaining the roll controllability obtained by the steering.

In the intermediate speed range of about 30 to 50 km/h, the steeringroll assist control L4 gradually reduces the effect strength thereofaccording to an increase in vehicle speed, and the effect strength isset to 0 at about 50 km/h.

Further, in the vehicle speed range in which the high rigidityself-standing control L6 and the self-standing auxiliary spring controlL5 are not started, there is no difference whether the second rockingcontrol switch 45 is in the ON or OFF state, and it is possible to rollthe vehicle body even when the second rocking control switch 45 isturned on.

Meanwhile, when the throttle is fully closed and the second rockingcontrol switch 45 is turned on, the self-standing auxiliary springcontrol L5 is started from a time point when the vehicle speed reachesthe low speed range (about 15 km/h or less). The self-standing auxiliaryspring control L5 gradually increases the effect strength (rockingrestricting force) from the low speed range to the ultra low speed range(about 3 km/h or less). Accordingly, wobbling at a low speed can bereduced during deceleration while allowing rolling of the vehicle body,and it is possible to establish both the self-standing during stoppageand the controllability similar to a two-wheeled vehicle.

When reaching the ultra low speed range, the high rigidity self-standingcontrol L6 is started instead of the self-standing auxiliary springcontrol L5. Accordingly, self-standing of the vehicle can be performedbefore stoppage. Therefore, since the high rigidity self-standingcontrol L6 is continued with the self-standing auxiliary spring controlL5, it is possible to easily and securely stop the two front wheelsrocking vehicle 1 in a self-standing state.

In addition, during restarting from the high rigidity self-standing,even when various roll moments (due to a load, luggage, or the like) areapplied to the vehicle body, since the rocking torque during the highrigidity self-standing is maintained by the offset cancellation controlL7, it is possible to reduce the wobbling during release of theself-standing.

As described above, the rocking control device for the two front wheelsrocking vehicle 1 according to the embodiment includes a high rigidityself-standing controller 56 that executes a high rigidity self-standingcontrol L6 that locks the rocking of the two front wheels rockingvehicle 1 and that assists a self-standing of the two-wheeled rockingvehicle 1, a switch that switches the high rigidity self-standingcontrol L6 to ON or OFF state, and an offset cancellation controller 57that executes an offset cancellation control L7 that maintains theself-standing state of the two front wheels rocking vehicle 1 until apredetermined traveling state is established when the high rigidityself-standing control is switched off.

According to this configuration, when the high rigidity self-standingcontrol L6 is turned off during the high rigidity self-standing controlL6, since self-standing assistance of the high rigidity self-standingcontrol L6 is maintained until a vehicle speed, a distance traveled, andso on, becomes to a predetermined traveling state, variation in rollposture when the high rigidity self-standing control L6 is released canbe suppressed.

In addition, in the rocking control device for the two front wheelsrocking vehicle 1 according to the embodiment, the high rigidityself-standing control L6 is released when a vehicle speed of the twofront wheels rocking vehicle 1 exceeds a predetermined speed.

According to this configuration, as the rocking lock is released whenthe predetermined speed is exceeded, an appropriate rollable drivingstate can be provided even when the rocking lock is applied on adownhill road or the like.

In addition, in the rocking control device for the two front wheelsrocking vehicle 1 according to the embodiment, a self-standing auxiliaryspring controller 55 that executes a self-standing auxiliary springcontrol L5 that applies a restricting force to a rocking of the twofront wheels rocking vehicle 1 and that suppresses the rocking of thetwo front wheels rocking vehicle 1 before reaching the high rigidityself-standing control L6 is provided.

According to this configuration, since the two front wheels rockingvehicle 1 reaches the high rigidity self-standing control L6 via theself-standing auxiliary spring control L5 working in a direction inwhich the rocking of the two front wheels rocking vehicle 1 issuppressed, self-standing properties can be enhanced while allowingrolling of the vehicle body, and the two front wheels rocking vehicle 1can be naturally guided toward self-standing.

In addition, in the rocking control device for the two front wheelsrocking vehicle 1 according to the embodiment, the self-standingauxiliary spring control L5 strengthens a rocking restricting forceaccording to a decrease of a vehicle speed.

According to this configuration, the two front wheels rocking vehicle 1can be gradually guided to self-standing according to a decrease of thevehicle speed while allowing rolling of the vehicle body.

In addition, in the rocking control device for the two front wheelsrocking vehicle 1 according to the embodiment, the offset cancellationcontrol L7 weakens a rocking restricting force according to an increaseof the vehicle speed.

According to this configuration, since rolling is allowed graduallyaccording to an increase of the vehicle speed, it is possible totransition to a naturally rollable state while variation during releaseof the rocking lock is suppressed.

Further, the present invention is not limited to the embodiment and, forexample, the two front wheels rocking vehicle is not limited to athree-wheeled vehicle having two front wheels and a single rear wheeland also includes a four-wheeled vehicle having two front wheels and tworear wheels. While the offset cancellation control maintains a rockingrestricting force until reaching a predetermined distance traveled aftercontrol starts, the rocking restricting force may be maintained until avehicle speed exceeds a predetermined value. Similarly, theself-standing auxiliary spring control may be configured to weaken therocking restricting force according to a vehicle speed rather than adistance traveled.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the scope of the present invention. Accordingly, theinvention is not to be considered as being limited by the foregoingdescription, and is only limited by the scope of the appended claims.

What is claimed is:
 1. A rocking control device for a two front wheelsrocking vehicle having a pair of left and right front wheels andconfigured to laterally rock a vehicle body, the rocking control devicefor the two front wheels rocking vehicle comprising: an actuator thatexecutes a first rocking control that assists a roll operation of arider of the two front wheels rocking vehicle and a second rockingcontrol that allows a self-standing of the two front wheels rockingvehicle without support by the rider during stoppage of the two frontwheels rocking vehicle, a high rigidity self-standing controller thatexecutes a high rigidity self-standing control that locks the rocking ofthe two front wheels rocking vehicle and that assists the self-standingof the two front wheels rocking vehicle, a switch that switches thesecond rocking control and the high rigidity self-standing control to ONor OFF state, and an offset cancellation controller that executes anoffset cancellation control that maintains the self-standing state ofthe two front wheels rocking vehicle until a predetermined travelingstate is established when the high rigidity self-standing control isswitched off, wherein the switch uses a throttle grip of the two frontwheels rocking vehicle as an operating part so that the switch isoperated by operation of the throttle grip.
 2. The rocking controldevice for the two front wheels rocking vehicle according to claim 1,wherein the high rigidity self-standing control is switched off when avehicle speed of the two front wheels rocking vehicle exceeds apredetermined speed.
 3. The rocking control device for the two frontwheels rocking vehicle according to claim 1, further comprising aself-standing auxiliary spring controller that executes a self-standingauxiliary spring control that applies a restricting force to a rockingof the two front wheels rocking vehicle that suppresses the rocking ofthe two front wheels rocking vehicle before reaching the high rigidityself-standing control.
 4. The rocking control device for the two frontwheels rocking vehicle according to claim 3, wherein the self-standingauxiliary spring control strengthens a rocking restricting forceaccording to a decrease of a vehicle speed.
 5. The rocking controldevice for the two front wheels rocking vehicle according to claim 1,wherein the offset cancellation control weakens a rocking restrictingforce according to an increase of a vehicle speed.
 6. The rockingcontrol device for the two front wheels rocking vehicle according toclaim 1, wherein the second rocking control and the high rigidityself-standing control are switched to the OFF state by the switch whenthe throttle grip as the operating part of the switch is rotated betweenfully closed and fully opened positions, and the second rocking controland the high rigidity self-standing control are switched to the ON statewhen the throttle grip as the operating part of the switch isover-stroked past the fully closed position.